Abstract: In order to realize the recycling of the secondary resources, the investigation of geopolymer synthesis was presented by utilizing lead or zinc smelting slag as the main Si-Al source material, the desulfurized gypsum and water glass as the activators. The influences of the pre-grinding time of smelting slag, mixed-grinding time of smelting slag and activators, dosage of desulfurized gypsum, dosage of water glass on the compressive strength of geopolymer were investigated by orthogonal experiment. As the results showed, the highest 3-day, 7-day and 28-day compressive strength of geopolymer samples were 26.03 MPa, 31.22 MPa and 36.48 MPa respectively when the pre-grinding time of smelting slag was about 60min, the mixed-grinding time of smelting slag and activators was about 70min, the dosage of desulfurized gypsum was about 4wt% and water glass was about 9wt%. XRD and SEM analysis of samples prepared by the best processing conditions indicated that the geopolymer had the dense microstructure composed of homogenous gel and acicular AFt crystal, and the incompletely reacted smelting slag was closely cemented by the gel phase and the compressive strength was found to be enhanced.